Centrifugal separator



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CENTRIFUGAL SEFARATGR.

Application led May 10, 1921. Serial No. 468,443.

To ZZ 'whom t may commet.'

Be it knownthat I, VVLLIAM BInoHALL, a citizen of the United States, anda resident of ilshbourne, in the county of Montgomery and State ofPennsylvania, have invented an improvement in Centrifugal Separator ofwhich the following is a specification.

My invention relates -to centrifugal separators adapted for theseparation of mixtures of solids and liquids, `and comprises certainimprovements which have been embodied in the construction disclosed inmy co-pending application filed April 11921, Serial Number 457,652, andit has for one V of its objects broadly to provide means whereby thepores or interstices in the porous lining` in the separator shell orouter wall structure shall be maintained in free and open condition tothereby insure that the separator shall function efficiently at alltimes.

@ther and more specific objects of the invention are to provide meansfor causing air or other Suitable fluid to flow through the said poresor interstices inwardly or in a direction in opposition to thecentrifugal force of the separator; to provide means for properly timingthe delivery of the air or other suitable fluid into ychambers betweeninner and outer `wall portions of the cylin drical wall structure ofthesaid separator; to provide an efficient means for removing from theinside surface of the cylindrical wall structure of the separator thematerial deposited thereon and conveying the same therefrom; and also toprovide means for preventing the clogging of certain portions of thepassageways employed for distributing the mixture of solids and liquidsto be separated.

Other objects and advantages of my invention will be pointed out in thedetailed description thereof which follows or will be apparent from suchdescription.

In order that the invention may be more readily understood, referencemay be had to the accompanying drawingl in which I have illustrated oneconvenient embodiment thereof. However, it will loe understood that thesaid invention is susceptible of embodiment in other formsr ofconstruction than that shown and that changes in the details ofconstruct-ion within the scope of the claims may be made withoutdeparting` from the said invent-ion.

In the drawing:

Figure l is a vertical sectional View of a centrifugal separatorembodying my invention taken along the line 1-1 of Figure 2;

Figure 2 is a view taken along the line 2 2 of lFigure l;

Figure 3 is a vertical sectional view taken along the lines 3-3 ofFigure 2;

F'gure i is a transverse sectional view taken along the line l-4 ofFigure l;

Figure 5 is a transverse sectional view of portion of the separatortaken along the line 5h?) of Figure 3; and

Figure 6 is a transverse sectional view of a portion of the separatortaken along the line 6 6 of Figure 3.

Referring to the drawing: l designates a centrally situated hollow shaftterminating at its lower end in a solid portion 2 `supported in astationary bearing 3, which in turn is supported upon sills, portionsonly of which are shown at 4. The upper portion of the shaft extendsthrough and is supported in a bearing structure 5 having paralleloppositely extending projections 6 by means of which it is supported onthe I-beams or sills 7.

The mixtures of solids and liquids to be separated are delivered fromany suitable source of supply, as for instance a reservoir (not shown),into the upper end portion of the hollow shaft, the said upperendportion being broken away so that it is not shown, and flow .downwardinto the lower portion of the shaft, from which they are dischargedthrough openings l() in the shaft and through openings l1 in acylindrical hub portion 14e surrounding the said shaft into thepassageways of the radially extending arms l5 and i6 which are integralwith the cylindrical hub portion let. These distributing arms 15 and 16,in the construction shown, extenddiametrically of the cylindricalseparator and in opposite directions from each other. It will beunderstood that the number of distributing arms may be increased ifdesired, also that only onet distributing arm may be employed.

The outer end portions of the distributing arms are curved and ext-endedrearwardly, as indicated at 20, and the forward or front wall thereof isterminated, as indicated at 2l. a distance in front of the end of theopposing side of the said arm. The portions of the rear sides of thesaid arms which project beyond the ends at 2l of the opposite sidesthereof are substantially concentric members 8st and 35.

28V are secured to the outer cylindrical solid wall 230 of sheet metalin any suitable inanner, also preferably by welding. rllhe upper and.lower end portions of the vporous sheet vor laver 25 are clampedbetween clamping bands 32 and 33 and the inner edges of the rlhe lowerside of the member Sil is inclined upwardly and outwardly andco-operates with the inwardly and down 7ardly inclined upper surface ofthe member 27 while the upper side of the 'lower member 35 is inclinedoutwardly and downwardly andy co-operates with the inwardly and upwardlyinclined bottom surface of the member 23 *The said members 3st and 35are detachably secured .in any suitable manner, as by screws, to thecylindrical outer wall member 80 of the wall structure; rlhe innersurfaces of the clamping bands 82 and are seated against shouldersformed by downwardly and upwardly extending projections 36 and 37, the

l former 'being formed upona top cover meniber 4:0 of the separator,while the latter is formed upon an outer rim portion Ll-l carried byspiders or arms 4t2 which project radially from a hub portion 43surrounding the solid portion 2 of the shaft l and being supported uponthe upper edge of the bear- Y .ing 3 of the said shaft.

Thile the top cover member l0 is shown in Athe form of acontinuousplate-lilre structure, itis to be understood that the saidmember may consist of an outer annulary rim portion Vconnected toV andsupported upon the hub 50 mounted upon theV shaft 1 and contacting atits lower end with the upper end of the cylinder la. The upper endportion of the solid cylindrical wall 30 secured to the peripheralsurface of the memberVLi-O while the lower end thereof is secured to theperipheral surface of the annular rim portion il carried upon thespiders i-2.

Although the'outer and inner cylindrical portions of the wall structure,constituting the separating medium of the separator, are shown as beingcontinuous, it will be understood that the said wall structure may bedivided into sections as shown in my copending application aforesaid.Rotation of the shaft l and of the top member Li0 and the lower memberComprising ythe parts Lil and 42 and upon which the outer wall structureof the apparatus is supported is effected tion the hub 50 is providedwith a gear Glv which mesheswith a pinion 62 secured to the lowerend ofa shaft 63 supported in a bearing upon the bearing structure 5previously referred to. The upper end of the y'shaft 63'is provided witha pinion Gel which l is larger than the pinion 62, which pinion is inengagement with a gear 65 which is secured to the lhollow shaft l. It isapparent, therefore, that the shaft l is driven by the power applied to'the pulley 60 and alsofthat it is driven or rotated in the samedirection asthe pulley 60 and the portion of the structure connectedthereto. It is also apparent that the relation of the intermediatedriving gears to each other is such that the said lshaft and thedistributing arms carried thereby are rotated at greater speed than thesurroundingcylindrical wall structure of the said apparatus.

' In the operation of the 'device a mixture of solid and liquidmaterials is delivered to the hollow shaft l and is delivered againstthe inside surface of the: porous sheet or layer 25 'The solid portionof the mixture thus delivered against the said porous layer or sheet isretained thereon, as described in detail in my application aforesaid,while the liquid content of the mixture through the said layer-and iscaught or lodged in the compartments formed between i the inner wallsection comprising the parts 25 land 26 andthe outer solid wall 30 bymeans of the rip-right or vertical strips 70, the opposite edges ofwhich are secured, preferably by welding, to the inner and outersurfaces respectively ofthe metal sheets 8O and 25. In a mannerwhichwill be heieinafterfully described, air or other suitable fluid underpressure is delivered also to these compartments and fiows inwardlythrough the porous sheet or layer 25 for the purpose Vpreviously statedherein. In order that the 1'iquid whichcollects in these compartmentsmay be discharged therefrom without permitting the voutflow of the airor other fluid therefrom through the passageways provi-ded for thedischarge of the liquid, `fhave provided the said liquid dischargepassageway-s comprising a relatively large intermediate portion 75 thebottom of which forms a valve seat for the ieception of a ball floatvalve Twhich closes the escapes innerfor'upper end of-the sinallerportion 7T of `the said .discharge opening. For the purpose ofdelivering the liquid from the respective compartments l have rprovidedtwo sinall ho'les *80 4which are spaced froni yeach other and `whichextend through the parts'28 and and are joined-at their lower ends toopposite side portions of the interniediaterelativelyllarge portion kofthe liquid discharge lnzissageiiziyf. The lower portions ofthe vholes 80are situated in such relation tothe relatively 'large portion 75 of the76 in the position as shown in Figure e passageway that they fornigrooves or passageways upon opposite sides thereof to per- -niit theliow of water downwardly through the Isaid passageway when the lioatvalves 76 are `lifted or raised by the presence of liquid iin therelatively 'large portion 75 of the passageways. TWhen the portions ofthepassagewayszcontain liquid the flow of .air or other suitable gaseousfluid therethrough is prevented and when rthe liquid `has escaped fromthe said passageways so Aas `to permit the seating'of the fica-t valvesY of the drawing the outflow of air through the liquid dischargepassageways is prevented `by the said valves,

For the purpose of removing troni the inner-surface of the lporous layeror sheet 25 thesolid-component of the mixture which is retained thereon:I 'have provided cylindri- -cal members 90, one of which is supportedupon"the'outerforward end portion of each lof thefdistributing arins l5and le. rilhe said/cylinders are slotted, asindicated at 9i, andtheforward edges of the rear side of the -saidslot-s are situatedpractically in contact with the inner -surlface ofthe said porous sheetor layer 25 so that as the said cylindrical members travel forwardly inrelation to-the cylindrical wallstructure of the separator the saidsolid component is scraped freni-the surface ofthe sheet 25, which con--stitutesfthe inner sheet or layer of the se rating wallstructure. Byreason of' the forward -rotary inoveinent of the said cylindricalinenibers, the solid inaterial thus removed passes throughthe said slotsinto the interiorof the cylinders and is conveyed downwardly therein bythe spiral conveyors 93 which vare situated within the said cylindricalmembers and are supported upon the revoluble shafts 9i which in turn aresupported at'their lower ends in hearings 95 Iintegral vwith the innerends of the bars 96 which extend inwardly troni the lower end.portionsof the said cylinders,l as best shown in Figures Sand 5. Theupper endportions ofthe revoluble shafts 9d are supported in hearings 92which are integrally connected to the:upper end portions ofthe cylinders90. Apinion97 .is secured to each of the shafts IQtabove the hearings92which pinion is in engagement lwith an `internal spur gear 98 ,eso

upon the inner side of the projection-BG. Inyiew of the fact that thedistributing arins y15 and i6 are rotating in the saine direction as hutat a greater speedithan the gear 98, it `will he apparent that theshaffts 1 9st and the spiral conveyers 93 carried therehy rotate in aclockwise direction vopposite that of the direction in which thedistributing arnis l5 and 16 and the separating wall structure rotate,as indicated hy the arrow- 100 in Figure 2 of the drawing.

ln the eniploynient of the machine `it is necessary, at least in thecases off soine niiX- tures of solids and liquids, that ineans heprovided to l-:eep the pores or interstices of the porous sheet or layer25 free in order that the separation of the solid and liquid coinaonentsniay he properly and efficiently effected. For this purpose l haveprovided ineens for supplying air under pressure sucannular 'tlangeineinber 106 is seated in an annular depression formed in the upper endof the huh {it} into which the upper ends of the liassageways il() open.rllliese passageways entend downw rdly through the hub 50 parallel withthe shaft l and then outwardly through the iii-einher -i-tl, radiatingfroni the anis of the shaft l as a center, as is apparent freni Figures2 and et. The outer ends of the said passageways il() open into theupper ends of the con'ipartinents formed by the vertical strips "0between the inner and outer walls of the cylindrical wall structure ofthe separator. lhere should be at least as i tiny of these passagewaysas there are compartments formed yby said vertical strips 70. r)flicannular flange 1G26 is previdedrwith two diai'netrically opposed ovalopenings lll through which openings air under pressure which has beendelivered to theY annular chaniber 105 from a pipe 10i is adapted to bedischarged successively into the upper ends of the passagcways 11G.'lhese holes are so arranged with respect to the distributing arins l5and it; that the air is delivered successively into the passageway/'swhich open at their outer ends into compartments fori'ned hy thevertical strips 7.() which occupy positions ininiediately in front or inadvance of the said distributing arins. For instance, it will beohserved by reference to Figure 2 that the for- ."ard end of' theopening` lll sho-wn therein is extended a slight distance over the up-'J per end oit the passageway 110. The air under pressure, therefore, isdelivered into the compartment which occupies a position immediately infront and adjacent to the cylindrical member 90 upon the arm 16. Uponthe further rotation of the two rotating members the said oval opening111, which is shown in Figure 2, moves forwardly with respect to themember Ll0 and the parts secured to and rotating therewith so that thesaid opening 111 next passes over the upper end of the succeedingpassageway 110, and so on over and over during the'operation of themachine.

The air or other suitable gaseous vvfluid which is delivered into thecompartments formed by the vertical strips 7() between the outer andinner walls of the wall structure iows inwardly through the pores of theporous inner sheet or layer of the wall structure, so that the saidpores are prevented from being clogged or closed. By this means theapparatus is maintained in condition to perform satisfactory andefficient work.

As already pointed out, the air or other gaseous fluid is prevented frompassing outwardly through the passagevmys leading from the bottoms ofthe compartments formed by the vertical strips TO either by the presenceof liquid in the said passageways or by the ball valves 7G in the largerf portion or section thereof.

In the continued use or operation of the apparatus it may happen thatthe material being treated will settle in the lower portion ofthe hollowshaft 1 and also that the open- Y ings or perforations leading from thesaid shafttherethrough and through the cylindrical hub 14; would becomeclogged. .In order to relieve or remove such clogged condition l haveprovided a pipe 115 which projects downward'into the hollow shaft 1 andterminates near the lower end thereof through which air or steam isadapted to be blown and forced into the said sha-ft to effect theagitation and breaking up of any deposit which may be formed therein orwithin the passageways 10 and 11 or within the passageways through the'distributing arms l5 and 15, so as to permit free passage of themixtures of solids and liquids through the said shaft and thepassageways through the said arms to the outer ends of the latter wherethe said mixture is thrown against the inner surface of the porous sheetor layer 25. As already stated, the solid component of the mixture isretained upon the inner surface of the said sheet while the liquidcontent thereof, under the infiuence of centrifugal force, passesthrough the pores thereof and is delivered into the compartments formedby the vertical strips situated at intervals in the space between theinner and outer wall members of the cylindrical wall structure.

Having thusdescribed my invention, what I claim and desire to secure byLetters Patent is:

1. In a centrifugal separator adapted for separating mixtures of solids;and liquids, the combination of rotating separating means, radial meansfor delivering a mixture of solids and liquids on to the inner surfaceof said separating means, said radial means being rotatable the liquidcontent thereof escaping and leaving the solid content of the mixture onsaid surface, means.

y surface of said separating means, the liquid thereof escaping andleaving the`solid content of the mixture on said surface, a cylindermounted on the rotatable delivering means a distance from the center ofrotation of said means and in adjacent relation to the inner surfaceA ofthe said separating means, said cylinder being provided with a slot, oneedge of which constitutes a scraper Vfor removing the said solid contentfrom the said surface and a conveyer mountedwithin the said cylinder forconveying the solid content from its point of removal and effecting itsdischarge from the said separator, the said conveyer being rotatableabout its own axis. Y

'3. ina centrifugal separator adapted 'for separating mixtures of solidsand liquids,

the combination of rotating separating means, means for delivering amixture of ysolids and liquids Onto the inner surface of said separatingmeans, the liquid thereof escaping and leavingV the solid content of themixture on said surface, a scraper for removing the said solid contentfrom the said surface, a spiral conveyer for convey` ing the said solidcontent from its point of removal and effecting its discharge from saidseparator, and means for causing rotation of said conveycr in adirection opposite the movement of the said scraper.

4:. ln a centrifugal separator adapted for separating` mixtures ofsolids and liquids, the combination of rotating cylindrical means forseparating mixtures of solids and liquids, rotating distributing meansfor sup-- plying the said mixtures onto the inner surface of the saidseparating means, means for rotating the said distributing means in thesame direction as but at a greater speed than that of the revolution ofthe said separating means.; a scraper carried by the said'disw tributingmeans for removing the solid con.

tent ofrthe' said mixture from the inside sur-v face of the saidseparating means, the said scraper being situated in front of the said:means for separating ini-xtures of solidsand liquids, rotatingdistributing means for sup= plying the said mixtures onto the innersurface ofthe said separating means, means for rotating the saiddistributing means in the same direction as but at agreaterv speed thanthat of the revolution of the said separat` ing means, a scraper carriedby the said dis-V tributing means for removing the solid content ofthesaidmixture from the insidesurface of the said separating means, thesaid scraper being situated in front of the said distributing means bywhich it is carried, a rotatable conveying means situated adjacent thesaid scraperfor receiving and conveying the said solid content away fromits point of removal and effecting its discharge from the saidseparator, and means for causing rotation of said conveyer in adirection opposite that of the direction of rotation of the saiddistributing means and the said separating means. i

6. In a centrifugal separator adapted for separating mixtures of solidsand liquids, the combination of cylindrical separating means, means forcausing rotation of said separating means,- a distributing arinforde`livering mixtures of solids and liquids onto the inner surface of saidseparating means, 4

the liquid thereafter escaping and leaving the solid content of themixtures on said surface, means for causing rotation of the saiddistributing` arm in the same direction as but at a greater speed thanthat of' the rotation of said separating means, means carried by thesaid distributing arm adjacent its outer end and adapted to remove thesolid contents of the said mixtures from the inside surface of the saidseparating means, and means situated adjacent' the said removing meansand traveling in unison therewith for conveying the material removedthereby from the said separator.

T.A In a centrifugalseparator adaptedL for separating` mixtures ofsolids and liquids, the combination of cylindrical separating means,means for causing rotation of said sejiarating means, a distributing`arm for delivering mixtures of solids and liquids onto the inner surfaceof said separating means, the liquid thereafter escaping and leaving thesolid content of the mixtures cnsaid surface, means for cansino"rotation of the said distributing arm in tne same direction 'i as but ata greater speed thanthat of the rotation of said separating means, meansiarried by the said distributing arm adjacent its outer end and adaptedto remove the solid contents .of the said mixtures from the insidesurface of thel said separating'means,

rotatable spiral conveyer supported in adjacent relation to the saidremoving meansand traveling in unison therewith, means for causing thesaid solid contents to be delivered to the said conveyer as they arere.- moved from the said separating means, and

means for causing rotation of the said spiral cenveyer in a directionthe reverse of the bodily traveling: movement thereof to effectdischarge ofthe said-solid contentsfromthe said separator. f

8. In a centrifugal separator adaptedv for separating mixtures of solidsand liquids, the combination of separating means comprising a lil-teringmember through which the liquid content of the mixture is adapted topass, due to the action of centrifugal force, andv upon the innersurface of Whichthe solid content of said mixture is adapted to beretained, means for removing the said solid content from the innersurface of said filtering member, and pneumatic mea-ns for suppying agaseous fluid und-er pressure successively tothe exterior sides ofVportions of the said filtering member infront ofthe said last mentionedmeans for maintaining the pores ofvsaid filtering member open.

9. In a centrifugal separator adapted for separating mixtures of solidsand liquids,v the combination of a rotatable separating means comprisingan inner perforated Wall and an outer imperforate Wall situated inspaced relation With respect to each other, means for closing the upperand lower ends of said space, means for dividing the said y space intocompartmentmmeans for delivs ering a mixture of solids and liquids tothe inner surface of the perforated Wall, the solid content of the saidmixture being deposited upon the inner surface of said Wall',` meansWhich is movable relatively'to the said perforated wall for removing thesolid content from the inner surface thereof and means for supplying agaseous `i'uid under pressure successively to the said coinpart ments asthey occupy positionsin front of the said means for removing the solid'content from the inner surface of said perfo` rated Wall for maintainingthe pores of the said perforated Wall in open condi-tion.

l0.` In a centrifugal separator adapted for separating mixtures ofsolids and liquids, the combination of a rotatable separating meanscomprising an inner perforated Wall andY an outer imperforate Wall,which Walls are situated in spaced relation with respect to each other,means for dividing the space between the said wallsinto a plurality ofclosed compartments, centrifugally acting means for supply mixtures ofsolids and liquids to the inner surface of the `inner perforated wall,means carried by the said centrifugally act-ing means for removing thesolid content of the. said mixture from the inner surface of the saidinner perforated wall, and means for supplying a vgaseous fluid underpressure successively to thesaid compartments as they reach positions infront of the said means for supplying the said mixtures to the saidseparating means, the. pressure of the said gaseous fluid within thesaid compartments causing the same to flow inwardly through theperforations of the said inner wall to maintain the said perforations inopen condition.

l1. In a centrifugal separator adapted for separating mixtures of solidsand liquids, the combination of cylindrical rotating separating meanscomprising inner and outer walls supported in spaced relation withrespect to each other and the inner walls comprising a sheet of porousmaterial, means for depositing the mixtures of solids and liquids to beseparated'upon the inner surface of the said rotating separating means,the liquid content thereafter escaping through the said porous sheetleaving the solid content upon the. inner sur-face of the said sheet,and means for supplying a. gaseous fluid under pressure to the spaceintermediate the said inner and outer walls and forcing the sameinwardly through the pores` of the said porous sheet in vopposition tocentrifugal force to maintain the saidpores free of solid material. V

12. In a centrifugal separator adapted for separating mixtures of solidsand liquids,

the combination of a rotating cylindrical.

separating means comprising inner and outer walls supported in spacedrelation with respect to each other, means for separating said spaceinto a plurality of closed compartments, rotating distributing means fordelivering mixtures of solids and liquids to the inner surface of theinner wall, the said distributing means rotating in the same directionas and at a greater speed than the separating means, and means forsupplying a gaseous fluid under pressure to the said compartmentssuccessively, the gaseous fluid being supplied successively immediatelyin advance. of the said distributing means.

13. In a centrifugalV separator adapted for separating mixtures ofsolids and liquids, the combination of a rotatable cylindricalseparating means comprising inner and outer walls supported lin spacedrelation vwith respect to each other, the inner wall comprising a layerof porous material,

means forclosing the upper and lowerl ends of the space between saidwalls, means for dividing the saidrspace vinto a plurality ofcompartments, distributing means for delivering mixtures'of solids andliquids to the inner surface ofthe inner wall, means for causingsimultaneous rotation of the separating and distributing means, thelatter being rotated in the same direction as but at a greater speedthan that of the rotation of the separating` means, and means forsupplying a gaseous fluid'under pressure successively to thesaidcompartments, substantially as described. l

14. In a centrifugal separator adapted for separating mixtures of solidsand liquids, the combination of a rotatable cylindrical separating meanscomprising inner and outer walls supported in spaced relation withrespect to each other, the inner wall comprising a layer of porousmaterial, means for closing the upper and lower ends of the yspacebetween said walls,ineans for dividing the said space into a pluralityof compartments, distributing means for delivering mixtures of solidsand liquids to t-he inner surface of the inner wall, means for causingsimultaneous rotation of the separating and distributing means,tlievlatter being rotated in the same direction as but at a greaterspeed than that of the rotation of the separating means, and means forsupplying a gaseous fluid successively to the saidcompartments underpressure sufficient to cause the same to flow inwardly through the poresof the said porous layer in opposition to the centrifugal forcedeveloped by the rotation of the said separating. means.

15. In a centrifugal vseparator adapted for separating mixtures ofsolids and liquids, the combination of a rotatable cylindricalseparating means comprising inner and outer walls supported in spacedrelation with respect to each other, the inner wall comprising a layerof porous material, means for closing the upper and lower ends of Vthespace between said walls, means for dividing the said space into aplurality of compartments, distributing means for des livering mixturesof solids and liquids to the inner surface of the inner wall, means forcausing simultaneous rotation of the separating and distributing means,the latter being rotated in thefsame direction as but at a greater speedthan that of the rotation of the separating means, and means .fordelivering a gaseous fluid to the said compartments successively,thedeliv'ery being made to that compartment immediately preceding thedistributing means andthe pressure of the gaseous fluid within the saidcompartment being su'fcient to cause the same to flow inwardly therefromthrough the pores of the said porous layer.

16. In a centrifugal separator adapted for separatingmixtures of solidsand liquids,

the combination of rotating i separating means comprising inner andouter walls supported in spaced relation to each other, the

binner wall including a layer of porous material, means for dividing thespace between the said walls into a plurality of closed compartments, achamber containing a gaseous fluid under pressure, a plurality ofpassageways terminating at their inner ends in operative relation to thesaid chamber and at their outer ends in the said compartments, and meansfor successively placing the inner ends of the said passageways incommunication with the said chamber whereby a gaseous fiuid underpressure may be delivered to successive compartments.

17. In a centrifugal separator adapted for separating mixtures of solidsand liquids, the combination of a rotating separating means comprisinginner and outer walls supported in spaced relation to each other and theinner wall including' a porous sheet, means for dividing the spacebetween the said walls into a plurality of closed compartments, rotatingmeans for supporting said separating means, said supporting rotatingmeans having passageways extending ra dially therein from the centralportion of the said separator and terminating at their outer ends in thesaid compartments, a stationary chamber containing a gaseous fluid underpressure, and rotating means intermediate the said chamber and the innerends of the said passageways for successively placing the said innerends in communication with the said chamber whereby a gaseous fluidcontained therein under pressure is distributed through the saidsuccessive passageways into successive compartments.

18. In a centrifugal separator adapted for separatingl mixtures ofsolids and liquids, the combination of a cylindrical separating meanscomprising` inner and outer walls supported in spaced relation to eachother, the inner wall including a sheet of porous material, means forclosing the upper and lower ends of the space between said walls, meansfor permitting liquids to escape from said space but preventing theescape of a gaseous fluid therefrom, means for causing rotation of saidseparating` means, and means for supplying a gaseous fluid to said spaceunder pressure sufficient to cause Iiow of the same inwardly through thepores of said porous sheet in opposition to the centrifugal forcegenerated by the rotation of said separating means.

19. In a centrifugal separator adapted for separating mixtures of solidsand liquids,the combination of a cylindrical separating means comprisinginner and outer walls supported in spaced relation to each other, theinner wall including a` sheet of porous material, means for (.ividingthe said space into a plurality of closed compartments, the saidcompartments having p'assageways leading therefrom, means forpermit-ting the passage of liquids through said passageways butpreventing the passage of a gaseous fluid therethrough, means forcausing rotation of said separating means, rotating means for deliveringmixtures of solids` and liquids to the inner `surface of the saidseparating means, the liquid content thereafter escaping into saidcompartments leaving the solid content upon the said surface, and meansfor supplying gaseous fiuids to said compartments under presuresufficient to cause the same to flow therefrom inwardly through thepores of said sheet of porous material.

20. In a centrifugal separator adapted for separating mixtures of solidsand liquids, the combination of a rotatable hollow shaft, a rotatablehollow separating means, one or more arms secured to said shaft androtating therewith and terminating adjacent the inner surface of saidseparating means, the said arm or arms having a passageway orpassageways for distributing the said miX- tures to said separatingmeans, and the said shaft having passageways communicating with thepassageway or passageways in said arm or arms, and the said shaft beingadapted to receive the said mixtures and to deliver the same throughsaid passageways. and means for delivering a gaseous uid under pressureinto said shaft for preventing the said passageways from becomingclogged up and interrupted. V

In testimony that I claim the foregoing as my invention,-I have hereuntosigned my name this 21st day of April, A. D., 1921.

WILLIAM BIRCHALL.

